A Two-Layer Minimal–to–MHD Framework for Orbital-Driven Geodynamo Reversals

This work introduces a dual-layer theoretical framework for understanding Earth’s magnetic-field reversals.

Layer A provides a minimal two-variable dynamical system that captures the essential nonlinear interactions between magnetic-field growth, flow damping, and long-period orbital forcing.

Layer B derives the physical meaning of all coefficients from first-principles magnetohydrodynamics (MHD), including the effects of rotation, Lorentz forces, viscosity, and time-dependent orbital acceleration.

The two layers combine mathematical simplicity with physical rigor, showing that small but persistent orbital forcing can naturally trigger transitions between stable magnetic states, oscillatory regimes, and full polarity reversals without fine-tuning.